You are trading cramped weekends inside for an outdoor room that actually gets used once the sun goes down. A solid fire pit and patio seating area completely changes how you use your yard, turning dead grass into the spot where everyone wants to hang out. The actual work of digging, pouring, and setting stone usually takes a long weekend once the materials arrive.
Late summer or fall is the absolute best time to buy patio furniture and line up contractors, because retailers are clearing space for winter inventory and landscapers are slowing down. Before you hand over any deposit, get at least three distinct quotes from local pros so you know what the job actually costs in your zip code.
Keep in mind that 0% for 18 months on purchases and balance transfers from date of account opening is a deadline, not free money. If you still have a balance left when those 18 months are up, the remaining amount gets hit with standard interest rates fast.